We are interested in proteins with biologically important functions, that achieve their activities through dynamic processes which result from structural changes. The two proteins that we are concerned with in this study, KcsA and P97, are excellent examples of such molecules. KcsA is a potassium ion channel from Streptomyces lividans, the understanding of which would have repercussions for a number of biological processes, such as nerve impulses. P97 is a protein involved in bilayer fusion, the structure of which would also further the understanding in a number of important areas of biology, an example of which would be the Ca2+-regulated fusion (exocytosis) of synaptic vesicles in the release of neurotransmitters.